linux-kernel - Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

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Message-ID: <4766E086.9090500@gmail.com>
Date:	Mon, 17 Dec 2007 21:48:06 +0100
From:	Rene Herman <rene.herman@...il.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	Ingo Molnar <mingo@...e.hu>, "David P. Reed" <dpreed@...d.com>,
	"H. Peter Anvin" <hpa@...or.com>, Paul Rolland <rol@...917.net>,
	Pavel Machek <pavel@....cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	rol@...be.net
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

On 17-12-07 17:12, Alan Cox wrote:

> I don't think we should be offering udelay based delays at this point.
> There are a lot of drivers to fix first. This is just one trivial example

I agree. This thread's too full of people calling this outb method a dumb 
hack. It's a well-known legacy PC thing and while in practice the udelay 
might be a functional replacement for a majority of cases (save the races 
you are finding) a delay proportional to the bus speed makes great sense 
certainly when talking to hardware that itself runs proportinal to the bus 
speed for example.

So, really, how about just sticking in this minimal version for now? Only 
switches the port to 0xed based on DMI and is all that is needed to fix the 
actual problem. This should be minimal and no-risk enough that it could also 
go to .24 if people want it to. It'll fix a few HP laptops (I'll try and 
get/verify the dv6000z DMI strings as well).

Ingo?

Signed-off-by: Rene Herman <rene.herman@...il.com>

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